Wow, you got off light at the vets. Poor little kitty.
Our cat got into the garage one time and I don't know from where, in the boat or on the garage floor, but ended up swallowing a hook with a dried roe sac on it I was just petting him and then noticed the fishing line hanging out of his mouth. He was purring at the time. Upon further inspection you could see it was attached to the back of his tongue. With me holding him and Paul using the plyers, there was no way could we get it off without kitty freak out city.
Off to the vet I went, but halfway there the line came unnattached and you could no longer see the hook or roe sac. I called the vet while in transit (it was the animal hospital as it was the weekend) and he suggested we do a wait and see if the hook was no longer visible. They said they could do xrays and such and exploratory surgery, but if it was a small hook the cat would probably pass it, same way they would a mouse bone etc.
I didn't sit and watch my kitty's daily ritual, but he was fine and that was 7 years ago. I think it must have passed
Joey